Removable and replaceable fuel nozzle holder assembly for an annular combustion burner



Oct. 1, 1968 3,403,510

REMOVABLE AND REPLAOEABLE FUEL NOZZLE HOLDER ASSEMBLY FOR AN ANNULAR COMBUSTION BURNER Filed NOV. 23, 1966 NVENTO ORNEY United States Patent O 3,403,510 REMOVABLE AND REPLACEABLE FUEL NOZZLE HOLDER ASSEMBLY FOR AN ANNULAR COM- BUSTION BURNER Lawrence J. Lauck, Wapping, Conn., assignor to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed Nov. 23, 1966, Ser. No. 596,698 3 Claims. (Cl. 6039.74)

ABSTRACT OF THE DISCLOSURE An annular combustion chamber in which the fuel nozzles are removable individually from the combustion chamber without removing or disassembling any engine part other than the fuel nozzle holder assembly. This is accomplished by providing an angular fuel nozzle holder assembly in combination with a radially movable swirler, the joint between the fuel nozzle and the swirler being one with universal motion.

This invention relates to a gas turbine engine and particularly to the manner of mounting fuel nozzles in a combustion chamber and it has as a feature the providing of an improved device of the character set forth.

The present invention, while not limited thereto, is particularly adapted to be used in a gas turbine engine similar to that disclosed in the Savin Patent No. 2,747,367 and in particular in a combustion chamber similar to that disclosed in copending application SN 596,698, filed Nov. 23, 1966, entitled Combustion Chamber With Floating Swirler Rings, both assigned to the present assignee of the present invention.

Many times during the operation of a gas turbine engine it becomes desirable or necessary to remove the fuel nozzles from the combustion chamber. In order to do this, in many instances, it is necessary to remove the combustion chamber completely from the engine. It is therefore a further feature of this invention to provide an arrangement by which the fuel nozzles are readily removable for inspection, cleaning and replacement without removing the combustion chamber or partially dismantling the engine.

It is a further feature of this invention to provide an arrangement of mounting the fuel nozzles so that while the fuel nozzles are readily removable, they can be assembled in their proper position within the combustion chamber so that the fuel and air are thoroughly mixed thereby providing for efiicient combustion.

Other features and advantages will be apparent from the specification and claims and from the accompanying drawings which illustrate an embodiment of the invention.

FIGURE 1 is a sectional view of a diffuser case and combustion chamber showing the device of the invention thereof.

FIGURE 2 is a fragmentary sectional view showing the radially movable swirler ring.

The invention is shown in a diffuser case 2 which surrounds combustion chamber 3 and is intended to be located between the compressor and turbine of a gas turbine power plant.

As shown in FIGURE 1, the combustion chamber is annular in form and consists of an Outer wall 4 and an inner wall 6, these walls being supported by a number of diffuser struts 7. These walls enclose a number of flame tubes 8 arranged in a ring within the outer and inner annular walls 4 and 6. Each flame tube 8 is substantially cup shaped and has an opening 10 in the base of the cup.

Positioned in each opening 10 is a radially movable 3,403,510 Patented Oct. 1, 1968 "ice swirler ring 12. Each swirler has an annular inner sleeve 14, an outer annular housing 16 and individual swirler vanes 18. Inner sleeve 14 has an opening within which a fuel nozzle 20, hereinafter described in greater detail, cooperates. As more clearly illustrated in FIGURE 2, the outer annular housing 16 has a stepped flange 26 extending radially outward from housing 16. Located upstream of this stepped flange is retaining ring 28, and flange 26 and ring 28 form a slot therebetween, within which flame cup flange 30 is inserted. This thereby secures the swirler axially while the stepped flanges permit the swirler to move radially.

Connected to the leading edge of the combustion chamber is contoured nose piece 32. The nose piece is a U- shaped member and is fixedly connected to the inner 6 and outer 4 walls. Rearwardly of nose piece 32, in outer wall 4 is opening 34. In diffuser case 2 is opening 36, opening 36 being spaced radially from opening 34 and being aligned radially with opening 34. Diffuser case 2 has an external housing 5 which may or may not be integral therewith and external housing 5 has external mounting pad 38 which has opening 39, through which the fuel nozzle holder assembly 40, hereinafter described, is inserted into combustion chamber 3 through openings 34 and 36. The fuel nozzle holder assembly 40 is connected to external housing 5 of diffuser case 2 by bolts 42.

Fuel nozzle holder assembly 40 includes an angular conduit 44, this conduit being secured to diffuser case 2 and extending through openings 34 and 36 into the annular combustion space between outer wall 4 and inner wall 6. Angular conduit 44 comprises a strut section 43 which extends inwardly from external housing 5 of diffuser case 2 at an acute angle with respect to the engine radius, this angular relationship with the engine radius being clearly illustrated in FIGURE 1. Attached to strut section 43 is a rearwardly extending section 45, rearwardly extending section 45 having means for locating and positioning fuel nozzles 20. Positioned inwardly from the external mounting pad 38 are integral radially spaced contoured discs 46 and 48. These discs are contoured to match the surrounding engine parts; in this instance, disc 46 is substantially the same shape as diffuser case 2 and disc 48 is substantially the same shape as outer wall 4. The discs 46 and 48 are positioned on angular conduit 44 such that they substantially seal openings 36 and 34 respectively. Therefore the discs serve the dual purpose of providing sealing surfaces and of serving as wall surfaces for outer wall 6 and diffuser case 2. The discs do not completely close openings 34 and 36 but have a circumferential gap 50 between the disc and surrounding wall, the gap being on the order of 0.065 inch.

The internal end of angular conduit 44 extends rearwardly between outer and inner walls 4 and 6 and supported internally in this rearwardly extending portion is fuel nozzle 20 the axis of this rearwardly extending end being coaxial with the swirler and concentric with the combustion chamber axis. In the embodiment of the invention as shown, the axis of the rearwardly extending end is offset from the combustion chamber axis so that as the combustion chamber expands thermally, the axis of the combustion chamber will then become coaxial with that of the rearwardly extending end of angular conduit 44 and therefore with fuel nozzle 20. As noted, fuel nozzle 20 is supported internally; however, a portion of the fuel nozzle extends axially past the end of the rearwardly extending portion of the angular conduit. The part of the fuel nozzle that extends past the end of the angular conduit is positioned slid'ably within an opening in inner sleeve 14 of swirler 12. The connection between fuel nozzle 20 and swirler 12 is a slidable one and inasmuch as the swirler is free to move radially, the slidable end and radially movable connection thereby provides and permits arcuate movement of the fuel nozzle holder assembly and hence permits the fuel nozzle to be engaged and disengaged from swirler 12. In this embodiment the cooperating surfaces between the fuel nozzle and swirler are shown as being cylindrical but it is understood that the shape of these surfaces is not limited thereto. They may be spherical or even line-to-line.

When the fuel nozzle holder assembly 40, containing fuel nozzle 20, is desired to be removed from the combustion chamber, bolts 42 are removed and the holder 40 is moved first outwardly and then forwardly. As the holder 40 is moved first outwardly and then forwardly, as a result of the angular shape of angular conduit 44, the contoured discs will move radially past the adjacent diffuser case 2 and outer wall 4. Since swirler 12 is radially movable and the fuel nozzle slidable therewithin, this outward and forward movement allows the fuel nozzle to disengage from the swirler. Once the fuel nozzle 20 has been disengaged from the swirler, the holder 40 can be guided out openings 34, 36 and 39 and the fuel nozzle removed therefrom.

Connected externally to angular conduit 44 are fuel supply tubes. As shown in this embodiment, tube 52 is the primary fuel supply tube and tube 54 is the secondary fuel supply tube, both tubes being connected to fuel nozzle 20 at the internal end of angular conduit 44.

It is to be understood that the invention is not limited to the specific description above or to specific figures shown, but may be used in other ways without departure from its spirit as defined by the following claims.

I claim:

1. In a gas turbine engine, an annular combustion chamber having inner and outer walls, a diffuser case surrounding said annular combustion chamber, an external housing surrounding said case, a plurality of cupshaped flame tubes connected to said walls, a plurality of annular swirlers supported for limited radial movement within said flame tubes, said swirlers being restrained axially, wherein the improvement comprises:

a plurality of fuel nozzles,

a plurality of fuel nozzle holder assemblies within which the fuel nozzles are positioned, each of said fuel nozzle holder assemblies including an angular conduit, the angular conduit comprising a strut section which extends inwardly at an acute angle with respect to the engine radius, from said housing thru aligned opening in the diffuser case and outer wall, the angular conduit also including a rearwardly extending section attached to the strut section at its innermost end, the rearwardly extending section having means at its downstream end for securing a nozzle thereto and for locating the nozzle so that it extends rearwardly past the end of the rearwardly extending section;

each of the rearwardly extending ends of the fuel nozzles being positioned in and extending axially thru a radially movable swirler in the combustion chamber, the connection therebetween being a slideable one, the slideable connection and the radial movement of the swirlers providing for arcuate movement of each assembly relative to its support thereby permitting removal of each of the individual fuel nozzle holder assemblies and fuel nozzles as a unitary assembly;

means on each of the strut sections for substantially sealing the openings in the diffuser case and the outer wall; and

means for securing each of the fuel nozzle holder as semblies to the external housing.

2. In a construction as in claim 1 wherein said means for substantially sealing said openings in said diffuser case and outer wall comprise:

a first contoured disc, said disc being integral with said strut section, the disc being substantially the same shape as said outer wall and substantially forming a portion thereof; and

a second contoured disc, said disc being integral with said strut section, the disc being substantially the same shape as said diffuser case and substantially forming a portion thereof.

3. In a construction as in claim 1, in which:

the cooperating surfaces between said rearwardly extending end of said fuel nozzle and said swirler are substantially cylindrical.

References Cited UNITED STATES PATENTS 2,422,214 6/ 1947 Meyer et al. -39.74 2,800,768 7/1957 Wheeler 60-3974 FOREIGN PATENTS 663,485 12/ 1951 Great Britain. 723,110 (I 2/ 1955 Great Britain.

JULIUS E. WEST, Primary Examiner. 

